Again, for the first case of membership: It is up to the CU to determine the eligibility. Once one is qualified, I doubt that NCUA would go back and question the CU process of membership approval. NCUA may complain and modify CU's current process to be more stringent, if it finds it to be loose (e.g., Air Force FCU). I doubt that it will ever go back and deny CU membership.
For the second case (which is independent of the first case of mebership eligibility), it is a different, but universal issue that deserves general attention for bank/CU/etc. customers.